CVE-2021-27131
Published: 16 May 2023
Summary
CVE-2021-27131 is a medium-severity Cross-site Scripting (CWE-79) vulnerability in Moodle Moodle. Its CVSS base score is 5.4 (Medium).
Operationally, ranked in the top 47.3% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-1633
Vulnerability details
Moodle 3.10.1 is vulnerable to persistent/stored cross-site scripting (XSS) due to the improper input sanitization on the "Additional HTML Section" via "Header and Footer" parameter in /admin/settings.php. This vulnerability is leading an attacker to steal admin and all user account…
more
cookies by storing the malicious XSS payload in Header and Footer. NOTE: this is disputed by the vendor because the "Additional HTML Section" for "Header and Footer" can only be supplied by an administrator, who is intentionally allowed to enter unsanitized input (e.g., site-specific JavaScript).
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Penetration testing submits XSS payloads to web applications, detecting cross-site scripting flaws for subsequent remediation.
Validates web inputs to reject script-related content that could produce XSS.
Output validation against expected content can reject or sanitize script content in generated web pages, reducing XSS exploitability.